Does anyone know if the service centers have the wall connectors in stock to sell? or can you purchase them online?
Check with your local SC, they were available at mine and also on line.
I got mine off e-bay, new in the box for quite a bit less than you will pay at your service center. Just search Tesla wall connector. Be patient, they come and go all the time on there.
Are you sure you need a wall connector? For 99.9% of drivers the nema 14-50 outlet is a far cheaper and better option.
If you're looking to only charge a Model 3, the HPWC is overkill, in that the car does not come with a dual onboard charger option and cannot accept more than the charge rate of the UMC that will come with the car (240V outlet, 40A). Save your $$$ and install a NEMA 14-50 outlet.
The Tesla Wall Connector looks pretty but overkill. I installed a NEMA 14-50 at home for $400.00 . You would be better off using the extra cash and buy a second cable to keep stored in your vehicle for emergency use. Anyway thats my experience and opinion.
Doesn't the cable cost almost the same as the TWC? If you plan on getting a second cable to leave at home, mind as well get the TWC.